Identification of the Promoter Antisense Transcript Enhancing the Transcription of the Equine Herpesvirus-1 Immediate-Early Gene

TL;DR

This study identifies a non-coding RNA that enhances the expression of a key viral gene in equine herpesvirus-1, aiding its replication.

Contribution

The discovery of a novel promoter-associated non-coding RNA (IE pancRNA) that enhances EHV-1 immediate-early gene transcription.

Findings

IE pancRNA is transcribed from the promoter region of the EHV-1 immediate-early gene.

IE pancRNA upregulates IE gene expression in the presence of ORF12.

Stable IE pancRNA expression increases EHV-1 infection in RN33B-A68B2M cells.

Abstract

Equine herpesvirus-1 (EHV-1) causes respiratory diseases, abortion, and encephalomyelitis in horses. The EHV-1 immediate-early (IE) protein, essential for viral replication, is transactivated by the binding of a multiprotein complex including the open reading frame 12 (ORF12) and some host factors to the IE promoter region. Promoter-associated non-coding RNAs (pancRNAs), which are transcribed from bidirectional promoters, regulate the transcription of neighboring genes in mammals and pathogens. In this study, we identified a novel pancRNA transcribed from across the areas of the 5′-untranslated region and a promoter of EHV-1 IE and named it IE pancRNA. IE pancRNA and mRNA were simultaneously expressed in EHV-1-infected RN33B-A68B2M cells. This pancRNA was also transcribed in RK13 and E. Derm cells, which are highly susceptible to EHV-1 infection. Furthermore, IE pancRNA upregulated IE gene expression in the presence of ORF12, and stable expression of IE pancRNA increased the number of EHV-1-infected RN33B-A68B2M cells. These results suggest that IE pancRNAs facilitate EHV-1 proliferation by promoting IE gene expression.

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